Sure. But if one central planner is better than two, because price controls would work better without competition, then it should stand to reason that even more than two planners would be even more effective. If the entire market were involved in price-setting, it should be optimal. Sure, there's probably a point of diminishing returns on how many people are needed to make price controls more efficient, but it seems likely that the point of diminishing returns isn't proximally close to 2.